Slightly less special casing in GtkWindow for gtk_widget_is_toplevel()
Slightly less special casing in GtkWindow for gtk_widget_is_toplevel()

Also take care of setting the resize-mode at realize time depending
on toplevelness.

Distrotech/gtk2,ahodesuka/gtk,jadahl/gtk,ahodesuka/gtk,jigpu/gtk,ebassi/gtk,chergert/gtk,alexlarsson/gtk,chergert/gtk,ebassi/gtk,simokivimaki/gtk,ebassi/gtk,simokivimaki/gtk,chergert/gtk,jigpu/gtk,alexlarsson/gtk,ahodesuka/gtk,jigpu/gtk,jessevdk/gtk,Sidnioulz/SandboxGtk,Adamovskiy/gtk,bratsche/gtk-,ebassi/gtk,chergert/gtk,grubersjoe/adwaita,jadahl/gtk,ahodesuka/gtk,grubersjoe/adwaita,Distrotech/gtk2,Lyude/gtk-,ahodesuka/gtk,davidgumberg/gtk,Lyude/gtk-,jigpu/gtk,simokivimaki/gtk,bratsche/gtk-,msteinert/gtk,Adamovskiy/gtk,Lyude/gtk-,davidgumberg/gtk,ahodesuka/gtk,chergert/gtk,davidt/gtk,jigpu/gtk,ahodesuka/gtk,Adamovskiy/gtk,jadahl/gtk,Sidnioulz/SandboxGtk,grubersjoe/adwaita,davidt/gtk,Distrotech/gtk2,Adamovskiy/gtk,Distrotech/gtk2,davidt/gtk,Lyude/gtk-,simokivimaki/gtk,alexlarsson/gtk,msteinert/gtk,jadahl/gtk,davidgumberg/gtk,Adamovskiy/gtk,grubersjoe/adwaita,bratsche/gtk-,jessevdk/gtk,jessevdk/gtk,ahodesuka/gtk,jessevdk/gtk,grubersjoe/adwaita,jessevdk/gtk,chergert/gtk,jigpu/gtk,grubersjoe/adwaita,grubersjoe/adwaita,Sidnioulz/SandboxGtk,jigpu/gtk,davidgumberg/gtk,Sidnioulz/SandboxGtk,alexlarsson/gtk,ebassi/gtk,jadahl/gtk,Lyude/gtk-,jessevdk/gtk,Sidnioulz/SandboxGtk,ebassi/gtk,jadahl/gtk,chergert/gtk,jigpu/gtk,davidgumberg/gtk,bratsche/gtk-,jadahl/gtk,davidt/gtk,grubersjoe/adwaita,Adamovskiy/gtk,msteinert/gtk,simokivimaki/gtk,msteinert/gtk,davidgumberg/gtk,msteinert/gtk,Lyude/gtk-,msteinert/gtk,alexlarsson/gtk,Distrotech/gtk2,alexlarsson/gtk,alexlarsson/gtk,bratsche/gtk-,simokivimaki/gtk,Lyude/gtk-,bratsche/gtk-,davidt/gtk,jadahl/gtk,Adamovskiy/gtk,Adamovskiy/gtk,chergert/gtk,alexlarsson/gtk,Distrotech/gtk2,davidt/gtk,Lyude/gtk-,davidgumberg/gtk,jessevdk/gtk,davidgumberg/gtk,Sidnioulz/SandboxGtk